Infidels.org's Meritt claims a contradiction exists here.
|“|| Matthew 5:1: And seeing the multitudes, he went up into a mountain: and when he was set, his disciples came unto him:
2 And he opened his mouth, and taught them, saying,
Luke 6:17 And he came down with them, and stood in the plain, and the company of his disciples, and a great multitude of people out of all Judaea and Jerusalem, and from the sea coast of Tyre and Sidon, which came to hear him, and to be healed of their diseases;
Luke 6:17 appears to be separate from 6:20, in other words, Jesus was on a plain healing the sick, the multitude thronged Him, and then He went up into a mountain to teach. This entire sequence is related in order in Mark 3:7-14, including the exact location of Tyre and Sidon's sea coast:
|“|| Mark 3:7 But Jesus withdrew himself with his disciples to the sea: and a great multitude from Galilee followed him, and from Judaea,
8 And from Jerusalem, and from Idumaea, and from beyond Jordan; and they about Tyre and Sidon, a great multitude, when they had heard what great things he did, came unto him.
9 And he spake to his disciples, that a small ship should wait on him because of the multitude, lest they should throng him.
10 For he had healed many; insomuch that they pressed upon him for to touch him, as many as had plagues.
11 And unclean spirits, when they saw him, fell down before him, and cried, saying, Thou art the Son of God.
12 And he straitly charged them that they should not make him known.
13 ¶ And he goeth up into a mountain, and calleth unto him whom he would: and they came unto him.
Mark 4:1 And he began again to teach by the sea side: and there was gathered unto him a great multitude, so that he entered into a ship, and sat in the sea; and the whole multitude was by the sea on the land.
The Sermon on the Mount appears to have occurred here in the Gospel of Mark, which relates the entire story. First Jesus withdrew with His disciples to the sea coast of Tyre and Sidon and was followed by a great multitude from Galilee, Judea, Jerusalem, Idumaea, Jordan, Tyre, and Sidon. (Luke 6:17, Mark 3:7-8) Jesus went into a ship with His disciples so He wouldn't get crowded by the multitude. (Mark 3:9-12) Jesus then went up to a mountain and taught. (Matthew 5:12, Mark 3:13-35) After all of this Jesus "began again to teach by the sea side" and again entered into a ship, teaching the multitude through parables from the ship. (Mark 4:1-34)
At any rate, both are true, Jesus was at a plain near the sea coast and then went up into a mountain. Mark appears to be the most detailed account of what happened with regards to location and detail. Luke 6:20 then skips all of the information about him moving from the plain to the sea to the mountain back to the sea and just starts the new paragraph talking about his famous sermon. Luke then probably focuses on what the writer considers most relevant, the huge multitude, the miracles, and the sermon, largely bypassing the specific details of the location changes that Mark delves into in detail.
Additionally, see John 6:1-3 for more confirmation that this sequence occurred:
|“|| John 6:1 After these things Jesus went over the sea of Galilee, which is the sea of Tiberias.
2 And a great multitude followed him, because they saw his miracles which he did on them that were diseased.
3 And Jesus went up into a mountain, and there he sat with his disciples.
Again, same sequence as before. Jesus crosses over the sea. He is followed by a huge multitude because of His miracles. Jesus then goes up into a mountain with His disciples. There is a transition back and forth from the plain to the sea to the mountain and back to the sea again, but without comparing all accounts this isn't as obvious.
Infidels.org's Meritt claims a contradiction exists here and asks, "How many beatitudes in the Sermon on the Mount" before providing the following list:
|“|| Matthew 5:3 Blessed are the poor in spirit: for theirs is the kingdom of heaven.
4 Blessed are they that mourn: for they shall be comforted.
5 Blessed are the meek: for they shall inherit the earth.
6 Blessed are they which do hunger and thirst after righteousness: for they shall be filled.
7 Blessed are the merciful: for they shall obtain mercy.
8 Blessed are the pure in heart: for they shall see God.
9 Blessed are the peacemakers: for they shall be called the children of God.
10 Blessed are they which are persecuted for righteousness' sake: for theirs is the kingdom of heaven.
11 Blessed are ye, when men shall revile you, and persecute you, and shall say all manner of evil against you falsely, for my sake.
Luke 6:20 And he lifted up his eyes on his disciples, and said, Blessed be ye poor: for yours is the kingdom of God.
Obviously it's not a 'contradiction' for one account to give more detail than another since neither passage states "there are X amount of beatitudes." The pattern of the Bible is that some accounts give more detail than others, complementing one another to form a cohesive whole and filling in spots left unexplained elsewhere.
Jim Meritt of Infidels.org claims the Bible contradicts itself on good deeds.
|“|| Matthew 5:16 Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.
Matthew 6:3 But when thou doest alms, let not thy left hand know what thy right hand doeth:
Jesus when doing miracles took this a step further, strictly telling those He healed not to tell anyone about what He'd done. (Mt. 8:4; 9:30; 12:16; Mk. 5:43; 7:36; Lk. 5:14; 8:56) As should be readily apparent, there is no contradiction here. Matthew 5:16 does not say to do good works before all - obviously those receiving alms will "see your good works and glorify your Father which is in Heaven." Matthew 5:16 is not a commandment to do alms openly in contradiction of 6:3, but to do them at all.
- Meritt, Jim (1992). A list of Biblical contradictions. Retrieved from http://www.infidels.org/library/modern/jim_meritt/bible-contradictions.html.